systemctl: reimplement systemctl in pure C without Vala/GObject

1 files changed, 1485 insertions, 0 deletions

diff --git a/src/systemctl.c b/src/systemctl.c
new file mode 100644
index 0000000000..8a7a2de403
--- /dev/null
+++ b/src/systemctl.c
@@ -0,0 +1,1485 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdio.h>
+#include <getopt.h>
+#include <stdbool.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <termios.h>
+#include <unistd.h>
+
+#include <dbus/dbus.h>
+
+#include "log.h"
+#include "util.h"
+#include "macro.h"
+#include "set.h"
+
+static const char *arg_type = NULL;
+static bool arg_all = false;
+static bool arg_replace = false;
+static bool arg_session = false;
+static bool arg_block = false;
+
+static int bus_iter_get_basic_and_next(DBusMessageIter *iter, int type, void *data, bool next) {
+
+        if (dbus_message_iter_get_arg_type(iter) != type)
+                return -EIO;
+
+        dbus_message_iter_get_basic(iter, data);
+
+        if (!dbus_message_iter_next(iter) != !next)
+                return -EIO;
+
+        return 0;
+}
+
+static int columns(void) {
+        static int parsed_columns = 0;
+        const char *e;
+
+        if (parsed_columns > 0)
+                return parsed_columns;
+
+        if ((e = getenv("COLUMNS")))
+                parsed_columns = atoi(e);
+
+        if (parsed_columns <= 0) {
+                struct winsize ws;
+                zero(ws);
+
+                if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) >= 0)
+                        parsed_columns = ws.ws_col;
+        }
+
+        if (parsed_columns <= 0)
+                parsed_columns = 80;
+
+        return parsed_columns;
+}
+
+static int list_units(DBusConnection *bus, char **args, unsigned n) {
+        DBusMessage *m = NULL, *reply = NULL;
+        DBusError error;
+        int r;
+        DBusMessageIter iter, sub, sub2;
+        unsigned k = 0;
+
+        dbus_error_init(&error);
+
+        if (!(m = dbus_message_new_method_call(
+                              "org.freedesktop.systemd1",
+                              "/org/freedesktop/systemd1",
+                              "org.freedesktop.systemd1.Manager",
+                              "ListUnits"))) {
+                log_error("Could not allocate message.");
+                return -ENOMEM;
+        }
+
+        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                log_error("Failed to issue method call: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        if (!dbus_message_iter_init(reply, &iter) ||
+            dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_ARRAY ||
+            dbus_message_iter_get_element_type(&iter) != DBUS_TYPE_STRUCT)  {
+                log_error("Failed to parse reply.");
+                r = -EIO;
+                goto finish;
+        }
+
+        dbus_message_iter_recurse(&iter, &sub);
+
+        printf("%-45s %-6s %-12s %-12s %-15s %s\n", "UNIT", "LOAD", "ACTIVE", "SUB", "JOB", "DESCRIPTION");
+
+        while (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_INVALID) {
+                const char *id, *description, *load_state, *active_state, *sub_state, *unit_state, *job_type, *job_path, *dot;
+                uint32_t job_id;
+
+                if (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_STRUCT) {
+                        log_error("Failed to parse reply.");
+                        r = -EIO;
+                        goto finish;
+                }
+
+                dbus_message_iter_recurse(&sub, &sub2);
+
+                if (bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &id, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &description, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &load_state, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &active_state, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &sub_state, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_OBJECT_PATH, &unit_state, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_UINT32, &job_id, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &job_type, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_OBJECT_PATH, &job_path, false) < 0) {
+                        log_error("Failed to parse reply.");
+                        r = -EIO;
+                        goto finish;
+                }
+
+                if ((!arg_type || ((dot = strrchr(id, '.')) &&
+                                   streq(dot+1, arg_type))) &&
+                    (arg_all || !streq(active_state, "inactive"))) {
+
+                        int a = 0, b = 0;
+
+                        printf("%-45s %-6s %-12s %-12s%n", id, load_state, active_state, sub_state, &a);
+
+                        if (job_id != 0)
+                                printf(" %-15s%n", job_type, &b);
+                        else
+                                b = 1 + 15;
+
+                        if (a + b + 2 < columns()) {
+                                if (job_id == 0)
+                                        printf("                ");
+
+                                printf("%.*s", columns() - a - b - 2, description);
+                        }
+
+                        fputs("\n", stdout);
+                        k++;
+                }
+
+                dbus_message_iter_next(&sub);
+        }
+
+        if (arg_all)
+                printf("\n%u units listed.\n", k);
+        else
+                printf("\n%u live units listed. Pass --all to see dead units, too.\n", k);
+
+        r = 0;
+
+finish:
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static int list_jobs(DBusConnection *bus, char **args, unsigned n) {
+        DBusMessage *m = NULL, *reply = NULL;
+        DBusError error;
+        int r;
+        DBusMessageIter iter, sub, sub2;
+        unsigned k = 0;
+
+        dbus_error_init(&error);
+
+        if (!(m = dbus_message_new_method_call(
+                              "org.freedesktop.systemd1",
+                              "/org/freedesktop/systemd1",
+                              "org.freedesktop.systemd1.Manager",
+                              "ListJobs"))) {
+                log_error("Could not allocate message.");
+                return -ENOMEM;
+        }
+
+        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                log_error("Failed to issue method call: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        if (!dbus_message_iter_init(reply, &iter) ||
+            dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_ARRAY ||
+            dbus_message_iter_get_element_type(&iter) != DBUS_TYPE_STRUCT)  {
+                log_error("Failed to parse reply.");
+                r = -EIO;
+                goto finish;
+        }
+
+        dbus_message_iter_recurse(&iter, &sub);
+
+        printf("%4s %-45s %-17s %-7s\n", "JOB", "UNIT", "TYPE", "STATE");
+
+        while (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_INVALID) {
+                const char *name, *type, *state, *job_path, *unit_path;
+                uint32_t id;
+
+                if (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_STRUCT) {
+                        log_error("Failed to parse reply.");
+                        r = -EIO;
+                        goto finish;
+                }
+
+                dbus_message_iter_recurse(&sub, &sub2);
+
+                if (bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_UINT32, &id, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &name, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &type, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &state, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_OBJECT_PATH, &job_path, true) < 0 ||
+                    bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_OBJECT_PATH, &unit_path, false) < 0) {
+                        log_error("Failed to parse reply.");
+                        r = -EIO;
+                        goto finish;
+                }
+
+                printf("%4u %-45s %-17s %-7s\n", id, name, type, state);
+                k++;
+
+                dbus_message_iter_next(&sub);
+        }
+
+        printf("\n%u jobs listed.\n", k);
+        r = 0;
+
+finish:
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static int load_unit(DBusConnection *bus, char **args, unsigned n) {
+        DBusMessage *m = NULL, *reply = NULL;
+        DBusError error;
+        int r;
+        unsigned i;
+
+        dbus_error_init(&error);
+
+        for (i = 1; i < n; i++) {
+
+                if (!(m = dbus_message_new_method_call(
+                                      "org.freedesktop.systemd1",
+                                      "/org/freedesktop/systemd1",
+                                      "org.freedesktop.systemd1.Manager",
+                                      "LoadUnit"))) {
+                        log_error("Could not allocate message.");
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                if (!dbus_message_append_args(m,
+                                              DBUS_TYPE_STRING, &args[i],
+                                              DBUS_TYPE_INVALID)) {
+                        log_error("Could not append arguments to message.");
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                        log_error("Failed to issue method call: %s", error.message);
+                        r = -EIO;
+                        goto finish;
+                }
+
+                dbus_message_unref(m);
+                dbus_message_unref(reply);
+
+                m = reply = NULL;
+        }
+
+        r = 0;
+
+finish:
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static int cancel_job(DBusConnection *bus, char **args, unsigned n) {
+        DBusMessage *m = NULL, *reply = NULL;
+        DBusError error;
+        int r;
+        unsigned i;
+
+        dbus_error_init(&error);
+
+        for (i = 1; i < n; i++) {
+                unsigned id;
+                const char *path;
+
+                if (!(m = dbus_message_new_method_call(
+                                      "org.freedesktop.systemd1",
+                                      "/org/freedesktop/systemd1",
+                                      "org.freedesktop.systemd1.Manager",
+                                      "GetJob"))) {
+                        log_error("Could not allocate message.");
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                if ((r = safe_atou(args[i], &id)) < 0) {
+                        log_error("Failed to parse job id: %s", strerror(-r));
+                        goto finish;
+                }
+
+                assert_cc(sizeof(uint32_t) == sizeof(id));
+                if (!dbus_message_append_args(m,
+                                              DBUS_TYPE_UINT32, &id,
+                                              DBUS_TYPE_INVALID)) {
+                        log_error("Could not append arguments to message.");
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                        log_error("Failed to issue method call: %s", error.message);
+                        r = -EIO;
+                        goto finish;
+                }
+
+                if (!dbus_message_get_args(reply, &error,
+                                           DBUS_TYPE_OBJECT_PATH, &path,
+                                           DBUS_TYPE_INVALID)) {
+                        log_error("Failed to parse reply: %s", error.message);
+                        r = -EIO;
+                        goto finish;
+                }
+
+                dbus_message_unref(m);
+                if (!(m = dbus_message_new_method_call(
+                                      "org.freedesktop.systemd1",
+                                      path,
+                                      "org.freedesktop.systemd1.Job",
+                                      "Cancel"))) {
+                        log_error("Could not allocate message.");
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                dbus_message_unref(reply);
+                if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                        log_error("Failed to issue method call: %s", error.message);
+                        r = -EIO;
+                        goto finish;
+                }
+
+                dbus_message_unref(m);
+                dbus_message_unref(reply);
+                m = reply = NULL;
+        }
+
+        r = 0;
+
+finish:
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static DBusHandlerResult wait_filter(DBusConnection *connection, DBusMessage *message, void *data) {
+        DBusError error;
+        Set *s = data;
+
+        assert(connection);
+        assert(message);
+        assert(s);
+
+        dbus_error_init(&error);
+
+        /* log_debug("Got D-Bus request: %s.%s() on %s", */
+        /*           dbus_message_get_interface(message), */
+        /*           dbus_message_get_member(message), */
+        /*           dbus_message_get_path(message)); */
+
+        if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL, "Disconnected")) {
+                log_error("Warning! D-Bus connection terminated.");
+                dbus_connection_close(connection);
+
+        } else if (dbus_message_is_signal(message, "org.freedesktop.systemd1.Manager", "JobRemoved")) {
+                uint32_t id;
+                const char *path;
+
+                if (!dbus_message_get_args(message, &error,
+                                           DBUS_TYPE_UINT32, &id,
+                                           DBUS_TYPE_OBJECT_PATH, &path,
+                                           DBUS_TYPE_INVALID))
+                        log_error("Failed to parse message: %s", error.message);
+                else {
+                        char *p;
+
+                        if ((p = set_remove(s, (char*) path)))
+                                free(p);
+                }
+        }
+
+        dbus_error_free(&error);
+        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
+static int wait_for_jobs(DBusConnection *bus, Set *s) {
+        DBusError error;
+        DBusMessage *m = NULL, *reply = NULL;
+        int r;
+
+        assert(bus);
+        assert(s);
+
+        dbus_error_init(&error);
+
+        dbus_bus_add_match(bus,
+                           "type='signal',"
+                           "sender='org.freedesktop.systemd1',"
+                           "interface='org.freedesktop.systemd1.Manager',"
+                           "member='JobRemoved',"
+                           "path='/org/freedesktop/systemd1'",
+                           &error);
+
+        if (dbus_error_is_set(&error)) {
+                log_error("Failed to add match: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        if (!dbus_connection_add_filter(bus, wait_filter, s, NULL)) {
+                log_error("Failed to add filter.");
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        if (!(m = dbus_message_new_method_call(
+                              "org.freedesktop.systemd1",
+                              "/org/freedesktop/systemd1",
+                              "org.freedesktop.systemd1.Manager",
+                              "Subscribe"))) {
+                log_error("Could not allocate message.");
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                log_error("Failed to issue method call: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        while (!set_isempty(s) &&
+               dbus_connection_read_write_dispatch(bus, -1))
+                ;
+
+        r = 0;
+
+finish:
+        /* This is slightly dirty, since we don't undo the filter or the matches. */
+
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static int start_unit(DBusConnection *bus, char **args, unsigned n) {
+        DBusMessage *m = NULL, *reply = NULL;
+        DBusError error;
+        int r;
+        unsigned i;
+        const char *method, *mode;
+        char *p = NULL;
+        Set *s = NULL;
+
+        dbus_error_init(&error);
+
+        method =
+                streq(args[0], "start")  ? "StartUnit" :
+                streq(args[0], "stop")   ? "StopUnit" :
+                streq(args[0], "reload") ? "ReloadUnit" :
+                                           "RestartUnit";
+
+        mode = arg_replace ? "replace" : "fail";
+
+        for (i = 1; i < n; i++) {
+
+                if (!(m = dbus_message_new_method_call(
+                                      "org.freedesktop.systemd1",
+                                      "/org/freedesktop/systemd1",
+                                      "org.freedesktop.systemd1.Manager",
+                                      method))) {
+                        log_error("Could not allocate message.");
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                if (!dbus_message_append_args(m,
+                                              DBUS_TYPE_STRING, &args[i],
+                                              DBUS_TYPE_STRING, &mode,
+                                              DBUS_TYPE_INVALID)) {
+                        log_error("Could not append arguments to message.");
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                        log_error("Failed to issue method call: %s", error.message);
+                        r = -EIO;
+                        goto finish;
+                }
+
+                if (arg_block) {
+                        const char *path;
+
+                        if (!dbus_message_get_args(reply, &error,
+                                                   DBUS_TYPE_OBJECT_PATH, &path,
+                                                   DBUS_TYPE_INVALID)) {
+                                log_error("Failed to parse reply: %s", error.message);
+                                r = -EIO;
+                                goto finish;
+                        }
+
+                        if (!s)
+                                if (!(s = set_new(string_hash_func, string_compare_func))) {
+                                        log_error("Failed to allocate set.");
+                                        r = -ENOMEM;
+                                        goto finish;
+                                }
+
+                        if (!(p = strdup(path))) {
+                                log_error("Failed to duplicate path.");
+                                r = -ENOMEM;
+                                goto finish;
+                        }
+
+                        if ((r = set_put(s, p)) < 0) {
+                                log_error("Failed to add path to set.");
+                                goto finish;
+                        }
+                        p = NULL;
+                }
+
+                dbus_message_unref(m);
+                dbus_message_unref(reply);
+
+                m = reply = NULL;
+        }
+
+        if (arg_block)
+                r = wait_for_jobs(bus, s);
+        else
+                r = 0;
+
+finish:
+        free(p);
+
+        if (s)
+                set_free_free(s);
+
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static int isolate_unit(DBusConnection *bus, char **args, unsigned n) {
+        DBusMessage *m = NULL, *reply = NULL;
+        DBusError error;
+        int r;
+        const char *mode = "isolate";
+        char *p = NULL;
+        Set *s = NULL;
+
+        dbus_error_init(&error);
+
+        if (!(m = dbus_message_new_method_call(
+                              "org.freedesktop.systemd1",
+                              "/org/freedesktop/systemd1",
+                              "org.freedesktop.systemd1.Manager",
+                              "StartUnit"))) {
+                log_error("Could not allocate message.");
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        if (!dbus_message_append_args(m,
+                                      DBUS_TYPE_STRING, &args[1],
+                                      DBUS_TYPE_STRING, &mode,
+                                      DBUS_TYPE_INVALID)) {
+                log_error("Could not append arguments to message.");
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                log_error("Failed to issue method call: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        if (arg_block) {
+                const char *path;
+
+                if (!dbus_message_get_args(reply, &error,
+                                           DBUS_TYPE_OBJECT_PATH, &path,
+                                           DBUS_TYPE_INVALID)) {
+                        log_error("Failed to parse reply: %s", error.message);
+                        r = -EIO;
+                        goto finish;
+                }
+
+                if (!(s = set_new(string_hash_func, string_compare_func))) {
+                        log_error("Failed to allocate set.");
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                if (!(p = strdup(path))) {
+                        log_error("Failed to duplicate path.");
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                if ((r = set_put(s, p)) < 0) {
+                        log_error("Failed to add path to set.");
+                        goto finish;
+                }
+                p = NULL;
+
+                r = wait_for_jobs(bus, s);
+
+        } else
+                r = 0;
+
+finish:
+        free(p);
+
+        if (s)
+                set_free_free(s);
+
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static DBusHandlerResult monitor_filter(DBusConnection *connection, DBusMessage *message, void *data) {
+        DBusError error;
+        DBusMessage *m = NULL, *reply = NULL;
+
+        assert(connection);
+        assert(message);
+
+        dbus_error_init(&error);
+
+        /* log_debug("Got D-Bus request: %s.%s() on %s", */
+        /*           dbus_message_get_interface(message), */
+        /*           dbus_message_get_member(message), */
+        /*           dbus_message_get_path(message)); */
+
+        if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL, "Disconnected")) {
+                log_error("Warning! D-Bus connection terminated.");
+                dbus_connection_close(connection);
+
+        } else if (dbus_message_is_signal(message, "org.freedesktop.systemd1.Manager", "UnitNew") ||
+                   dbus_message_is_signal(message, "org.freedesktop.systemd1.Manager", "UnitRemoved")) {
+                const char *id, *path;
+
+                if (!dbus_message_get_args(message, &error,
+                                           DBUS_TYPE_STRING, &id,
+                                           DBUS_TYPE_OBJECT_PATH, &path,
+                                           DBUS_TYPE_INVALID))
+                        log_error("Failed to parse message: %s", error.message);
+                else if (streq(dbus_message_get_member(message), "UnitNew"))
+                        printf("Unit %s added.\n", id);
+                else
+                        printf("Unit %s removed.\n", id);
+
+        } else if (dbus_message_is_signal(message, "org.freedesktop.systemd1.Manager", "JobNew") ||
+                   dbus_message_is_signal(message, "org.freedesktop.systemd1.Manager", "JobRemoved")) {
+                uint32_t id;
+                const char *path;
+
+                if (!dbus_message_get_args(message, &error,
+                                           DBUS_TYPE_UINT32, &id,
+                                           DBUS_TYPE_OBJECT_PATH, &path,
+                                           DBUS_TYPE_INVALID))
+                        log_error("Failed to parse message: %s", error.message);
+                else if (streq(dbus_message_get_member(message), "JobNew"))
+                        printf("Job %u added.\n", id);
+                else
+                        printf("Job %u removed.\n", id);
+
+
+        } else if (dbus_message_is_signal(message, "org.freedesktop.systemd1.Unit", "Changed") ||
+                   dbus_message_is_signal(message, "org.freedesktop.systemd1.Job", "Changed")) {
+
+                const char *path, *interface, *property = "Id";
+                DBusMessageIter iter, sub;
+
+                path = dbus_message_get_path(message);
+                interface = dbus_message_get_interface(message);
+
+                if (!(m = dbus_message_new_method_call(
+                              "org.freedesktop.systemd1",
+                              path,
+                              "org.freedesktop.DBus.Properties",
+                              "Get"))) {
+                        log_error("Could not allocate message.");
+                        goto oom;
+                }
+
+                if (!dbus_message_append_args(m,
+                                              DBUS_TYPE_STRING, &interface,
+                                              DBUS_TYPE_STRING, &property,
+                                              DBUS_TYPE_INVALID)) {
+                        log_error("Could not append arguments to message.");
+                        goto finish;
+                }
+
+                if (!(reply = dbus_connection_send_with_reply_and_block(connection, m, -1, &error))) {
+                        log_error("Failed to issue method call: %s", error.message);
+                        goto finish;
+                }
+
+                if (!dbus_message_iter_init(reply, &iter) ||
+                    dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_VARIANT)  {
+                        log_error("Failed to parse reply.");
+                        goto finish;
+                }
+
+                dbus_message_iter_recurse(&iter, &sub);
+
+                if (streq(interface, "org.freedesktop.systemd1.Unit")) {
+                        const char *id;
+
+                        if (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_STRING)  {
+                                log_error("Failed to parse reply.");
+                                goto finish;
+                        }
+
+                        dbus_message_iter_get_basic(&sub, &id);
+                        printf("Unit %s changed.\n", id);
+                } else {
+                        uint32_t id;
+
+                        if (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_UINT32)  {
+                                log_error("Failed to parse reply.");
+                                goto finish;
+                        }
+
+                        dbus_message_iter_get_basic(&sub, &id);
+                        printf("Job %u changed.\n", id);
+                }
+        }
+
+finish:
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+
+oom:
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+        return DBUS_HANDLER_RESULT_NEED_MEMORY;
+}
+
+static int monitor(DBusConnection *bus, char **args, unsigned n) {
+        DBusMessage *m = NULL, *reply = NULL;
+        DBusError error;
+        int r;
+
+        dbus_error_init(&error);
+
+        dbus_bus_add_match(bus,
+                           "type='signal',"
+                           "sender='org.freedesktop.systemd1',"
+                           "interface='org.freedesktop.systemd1.Manager',"
+                           "path='/org/freedesktop/systemd1'",
+                           &error);
+
+        if (dbus_error_is_set(&error)) {
+                log_error("Failed to add match: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        dbus_bus_add_match(bus,
+                           "type='signal',"
+                           "sender='org.freedesktop.systemd1',"
+                           "interface='org.freedesktop.systemd1.Unit',"
+                           "member='Changed'",
+                           &error);
+
+        if (dbus_error_is_set(&error)) {
+                log_error("Failed to add match: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        dbus_bus_add_match(bus,
+                           "type='signal',"
+                           "sender='org.freedesktop.systemd1',"
+                           "interface='org.freedesktop.systemd1.Job',"
+                           "member='Changed'",
+                           &error);
+
+        if (dbus_error_is_set(&error)) {
+                log_error("Failed to add match: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        if (!dbus_connection_add_filter(bus, monitor_filter, NULL, NULL)) {
+                log_error("Failed to add filter.");
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        if (!(m = dbus_message_new_method_call(
+                              "org.freedesktop.systemd1",
+                              "/org/freedesktop/systemd1",
+                              "org.freedesktop.systemd1.Manager",
+                              "Subscribe"))) {
+                log_error("Could not allocate message.");
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                log_error("Failed to issue method call: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        while (dbus_connection_read_write_dispatch(bus, -1))
+                ;
+
+        r = 0;
+
+finish:
+
+        /* This is slightly dirty, since we don't undo the filter or the matches. */
+
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static int dump(DBusConnection *bus, char **args, unsigned n) {
+        DBusMessage *m = NULL, *reply = NULL;
+        DBusError error;
+        int r;
+        const char *text;
+
+        dbus_error_init(&error);
+
+        if (!(m = dbus_message_new_method_call(
+                              "org.freedesktop.systemd1",
+                              "/org/freedesktop/systemd1",
+                              "org.freedesktop.systemd1.Manager",
+                              "Dump"))) {
+                log_error("Could not allocate message.");
+                return -ENOMEM;
+        }
+
+        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                log_error("Failed to issue method call: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        if (!dbus_message_get_args(reply, &error,
+                                   DBUS_TYPE_STRING, &text,
+                                   DBUS_TYPE_INVALID)) {
+                log_error("Failed to parse reply: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        fputs(text, stdout);
+
+        r = 0;
+
+finish:
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static int snapshot(DBusConnection *bus, char **args, unsigned n) {
+        DBusMessage *m = NULL, *reply = NULL;
+        DBusError error;
+        int r;
+        const char *name = "", *path, *id;
+        dbus_bool_t cleanup = FALSE;
+        DBusMessageIter iter, sub;
+        const char
+                *interface = "org.freedesktop.systemd1.Unit",
+                *property = "Id";
+
+        dbus_error_init(&error);
+
+        if (!(m = dbus_message_new_method_call(
+                              "org.freedesktop.systemd1",
+                              "/org/freedesktop/systemd1",
+                              "org.freedesktop.systemd1.Manager",
+                              "CreateSnapshot"))) {
+                log_error("Could not allocate message.");
+                return -ENOMEM;
+        }
+
+        if (n > 1)
+                name = args[1];
+
+        if (!dbus_message_append_args(m,
+                                      DBUS_TYPE_STRING, &name,
+                                      DBUS_TYPE_BOOLEAN, &cleanup,
+                                      DBUS_TYPE_INVALID)) {
+                log_error("Could not append arguments to message.");
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                log_error("Failed to issue method call: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        if (!dbus_message_get_args(reply, &error,
+                                   DBUS_TYPE_OBJECT_PATH, &path,
+                                   DBUS_TYPE_INVALID)) {
+                log_error("Failed to parse reply: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        dbus_message_unref(m);
+        if (!(m = dbus_message_new_method_call(
+                              "org.freedesktop.systemd1",
+                              path,
+                              "org.freedesktop.DBus.Properties",
+                              "Get"))) {
+                log_error("Could not allocate message.");
+                return -ENOMEM;
+        }
+
+        if (!dbus_message_append_args(m,
+                                      DBUS_TYPE_STRING, &interface,
+                                      DBUS_TYPE_STRING, &property,
+                                      DBUS_TYPE_INVALID)) {
+                log_error("Could not append arguments to message.");
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        dbus_message_unref(reply);
+        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                log_error("Failed to issue method call: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        if (!dbus_message_iter_init(reply, &iter) ||
+            dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_VARIANT)  {
+                log_error("Failed to parse reply.");
+                r = -EIO;
+                goto finish;
+        }
+
+        dbus_message_iter_recurse(&iter, &sub);
+
+        if (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_STRING)  {
+                log_error("Failed to parse reply.");
+                r = -EIO;
+                goto finish;
+        }
+
+        dbus_message_iter_get_basic(&sub, &id);
+        puts(id);
+        r = 0;
+
+finish:
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static int clear_jobs(DBusConnection *bus, char **args, unsigned n) {
+        DBusMessage *m = NULL, *reply = NULL;
+        DBusError error;
+        int r;
+        const char *method;
+
+        dbus_error_init(&error);
+
+        method =
+                streq(args[0], "clear-jobs")    ? "ClearJobs" :
+                streq(args[0], "daemon-reload") ? "Reload" :
+                streq(args[0], "daemon-reexec") ? "Reexecute" :
+                                                  "Exit";
+
+        if (!(m = dbus_message_new_method_call(
+                              "org.freedesktop.systemd1",
+                              "/org/freedesktop/systemd1",
+                              "org.freedesktop.systemd1.Manager",
+                              method))) {
+                log_error("Could not allocate message.");
+                return -ENOMEM;
+        }
+
+        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                log_error("Failed to issue method call: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        r = 0;
+
+finish:
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static int show_enviroment(DBusConnection *bus, char **args, unsigned n) {
+        DBusMessage *m = NULL, *reply = NULL;
+        DBusError error;
+        DBusMessageIter iter, sub, sub2;
+        int r;
+        const char
+                *interface = "org.freedesktop.systemd1.Manager",
+                *property = "Environment";
+
+        dbus_error_init(&error);
+
+        if (!(m = dbus_message_new_method_call(
+                              "org.freedesktop.systemd1",
+                              "/org/freedesktop/systemd1",
+                              "org.freedesktop.DBus.Properties",
+                              "Get"))) {
+                log_error("Could not allocate message.");
+                return -ENOMEM;
+        }
+
+        if (!dbus_message_append_args(m,
+                                      DBUS_TYPE_STRING, &interface,
+                                      DBUS_TYPE_STRING, &property,
+                                      DBUS_TYPE_INVALID)) {
+                log_error("Could not append arguments to message.");
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                log_error("Failed to issue method call: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        if (!dbus_message_iter_init(reply, &iter) ||
+            dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_VARIANT)  {
+                log_error("Failed to parse reply.");
+                r = -EIO;
+                goto finish;
+        }
+
+        dbus_message_iter_recurse(&iter, &sub);
+
+        if (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_ARRAY ||
+            dbus_message_iter_get_element_type(&sub) != DBUS_TYPE_STRING)  {
+                log_error("Failed to parse reply.");
+                r = -EIO;
+                goto finish;
+        }
+
+        dbus_message_iter_recurse(&sub, &sub2);
+
+        while (dbus_message_iter_get_arg_type(&sub2) != DBUS_TYPE_INVALID) {
+                const char *text;
+
+                if (dbus_message_iter_get_arg_type(&sub2) != DBUS_TYPE_STRING) {
+                        log_error("Failed to parse reply.");
+                        r = -EIO;
+                        goto finish;
+                }
+
+                dbus_message_iter_get_basic(&sub2, &text);
+                printf("%s\n", text);
+
+                dbus_message_iter_next(&sub2);
+        }
+
+        r = 0;
+
+finish:
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static int set_environment(DBusConnection *bus, char **args, unsigned n) {
+        DBusMessage *m = NULL, *reply = NULL;
+        DBusError error;
+        int r;
+        const char *method;
+        DBusMessageIter iter, sub;
+        unsigned i;
+
+        dbus_error_init(&error);
+
+        method = streq(args[0], "set-environment")
+                ? "SetEnvironment"
+                : "UnsetEnvironment";
+
+        if (!(m = dbus_message_new_method_call(
+                              "org.freedesktop.systemd1",
+                              "/org/freedesktop/systemd1",
+                              "org.freedesktop.systemd1.Manager",
+                              method))) {
+
+                log_error("Could not allocate message.");
+                return -ENOMEM;
+        }
+
+        dbus_message_iter_init_append(m, &iter);
+
+        if (!dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "s", &sub)) {
+                log_error("Could not append arguments to message.");
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        for (i = 1; i < n; i++)
+                if (!dbus_message_iter_append_basic(&sub, DBUS_TYPE_STRING, &args[i])) {
+                        log_error("Could not append arguments to message.");
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+        if (!dbus_message_iter_close_container(&iter, &sub)) {
+                log_error("Could not append arguments to message.");
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+                log_error("Failed to issue method call: %s", error.message);
+                r = -EIO;
+                goto finish;
+        }
+
+        r = 0;
+
+finish:
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        dbus_error_free(&error);
+
+        return r;
+}
+
+static int help(void) {
+
+        printf("%s [options]\n\n"
+               "  -h --help      Show this help\n"
+               "  -t --type=TYPE List only units of a particular type\n"
+               "  -a --all       Show all units, including dead ones\n"
+               "     --replace   When installing a new job, replace existing conflicting ones\n"
+               "     --system    Connect to system bus\n"
+               "     --session   Connect to session bus\n"
+               "     --block     Wait until operation finished\n\n"
+               "Commands:\n"
+               "  list-units                      List units\n"
+               "  list-jobs                       List jobs\n"
+               "  clear-jobs                      Cancel all jobs\n"
+               "  load [NAME...]                  Load one or more units\n"
+               "  cancel [JOB...]                 Cancel one or more jobs\n"
+               "  start [NAME...]                 Start one or more units\n"
+               "  stop [NAME...]                  Stop one or more units\n"
+               "  restart [NAME...]               Restart one or more units\n"
+               "  reload [NAME...]                Reload one or more units\n"
+               "  isolate [NAME]                  Start one unit and stop all others\n"
+               "  monitor                         Monitor unit/job changes\n"
+               "  dump                            Dump server status\n"
+               "  snapshot [NAME]                 Create a snapshot\n"
+               "  daemon-reload                   Reload daemon configuration\n"
+               "  daemon-reexecute                Reexecute daemon\n"
+               "  daemon-exit                     Ask the daemon to quit\n"
+               "  show-environment                Dump environment\n"
+               "  set-environment [NAME=VALUE...] Set one or more environment variables\n"
+               "  unset-environment [NAME...]     Unset one or more environment variables\n",
+               __progname);
+
+        return 0;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+
+        enum {
+                ARG_REPLACE = 0x100,
+                ARG_SESSION,
+                ARG_SYSTEM,
+                ARG_BLOCK,
+        };
+
+        static const struct option options[] = {
+                { "help",      no_argument,       NULL, 'h'         },
+                { "type",      required_argument, NULL, 't'         },
+                { "all",       no_argument,       NULL, 'a'         },
+                { "replace",   no_argument,       NULL, ARG_REPLACE },
+                { "session",   no_argument,       NULL, ARG_SESSION },
+                { "system",    no_argument,       NULL, ARG_SYSTEM  },
+                { "block",     no_argument,       NULL, ARG_BLOCK   }
+        };
+
+        int c;
+
+        assert(argc >= 1);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "hta", options, NULL)) >= 0) {
+
+                switch (c) {
+
+                case 'h':
+                        help();
+                        return 0;
+
+                case 't':
+                        arg_type = optarg;
+                        break;
+
+                case 'a':
+                        arg_all = true;
+                        break;
+
+                case ARG_REPLACE:
+                        arg_replace = true;
+                        break;
+
+                case ARG_SESSION:
+                        arg_session = true;
+                        break;
+
+                case ARG_SYSTEM:
+                        arg_session = false;
+                        break;
+
+                case ARG_BLOCK:
+                        arg_block = true;
+                        break;
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        log_error("Unknown option code %c", c);
+                        return -EINVAL;
+                }
+        }
+
+        return 1;
+}
+
+int main(int argc, char*argv[]) {
+
+
+        static const struct {
+                const char* verb;
+                const enum {
+                        MORE,
+                        LESS,
+                        EQUAL
+                } argc_cmp;
+                const int argc;
+                int (* const dispatch)(DBusConnection *bus, char **args, unsigned n);
+        } verbs[] = {
+                { "list-units",        LESS,  1, list_units      },
+                { "list-jobs",         EQUAL, 1, list_jobs       },
+                { "clear-jobs",        EQUAL, 1, clear_jobs      },
+                { "load",              MORE,  2, load_unit       },
+                { "cancel",            MORE,  2, cancel_job      },
+                { "start",             MORE,  2, start_unit      },
+                { "stop",              MORE,  2, start_unit      },
+                { "reload",            MORE,  2, start_unit      },
+                { "restart",           MORE,  2, start_unit      },
+                { "isolate",           EQUAL, 2, isolate_unit    },
+                { "monitor",           EQUAL, 1, monitor         },
+                { "dump",              EQUAL, 1, dump            },
+                { "snapshot",          LESS,  2, snapshot        },
+                { "daemon-reload",     EQUAL, 1, clear_jobs      },
+                { "daemon-reexec",     EQUAL, 1, clear_jobs      },
+                { "daemon-exit",       EQUAL, 1, clear_jobs      },
+                { "show-environment",  EQUAL, 1, show_enviroment },
+                { "set-environment",   MORE,  2, set_environment },
+                { "unset-environment", MORE,  2, set_environment },
+        };
+
+        int r, retval = 1, left;
+        unsigned i;
+        DBusConnection *bus = NULL;
+        DBusError error;
+
+        dbus_error_init(&error);
+
+        log_set_target(LOG_TARGET_CONSOLE);
+        log_parse_environment();
+
+        if ((r = parse_argv(argc, argv)) < 0)
+                goto finish;
+        else if (r == 0) {
+                retval = 0;
+                goto finish;
+        }
+
+        left = argc - optind;
+
+        if (left <= 0)
+                /* Special rule: no arguments means "list-units" */
+                i = 0;
+        else {
+                for (i = 0; i < ELEMENTSOF(verbs); i++)
+                        if (streq(argv[optind], verbs[i].verb))
+                                break;
+
+                if (i >= ELEMENTSOF(verbs)) {
+                        log_error("Unknown operation %s", argv[optind]);
+                        goto finish;
+                }
+        }
+
+        switch (verbs[i].argc_cmp) {
+
+        case EQUAL:
+                if (left != verbs[i].argc) {
+                        log_error("Invalid number of arguments.");
+                        goto finish;
+                }
+
+                break;
+
+        case MORE:
+                if (left < verbs[i].argc) {
+                        log_error("Too few arguments.");
+                        goto finish;
+                }
+
+                break;
+
+        case LESS:
+                if (left > verbs[i].argc) {
+                        log_error("Too many arguments.");
+                        goto finish;
+                }
+
+                break;
+
+        default:
+                assert_not_reached("Unknown comparison operator.");
+        }
+
+        if (!(bus = dbus_bus_get(arg_session ? DBUS_BUS_SESSION : DBUS_BUS_SYSTEM, &error))) {
+                log_error("Failed to get D-Bus connection: %s", error.message);
+                goto finish;
+        }
+
+        dbus_connection_set_exit_on_disconnect(bus, FALSE);
+
+        retval = verbs[i].dispatch(bus, argv + optind, left) < 0;
+
+finish:
+
+        if (bus)
+                dbus_connection_unref(bus);
+
+        dbus_shutdown();
+
+        return retval;
+}